1. This is because each enzyme has a specific active site on which only a particular substrate can bind. ,
2. This is because of Tyndall effect caused due to the scattering of light by colloidal particles of As S sol.
3. Chemisorption involves the formation ofa chemical bond between adsorbent and adsorbate molecule which involves high energy changes while in physisorption, the molecules of adsorbate and adsorbent arc held by weak van der Waals’ interactions.